# stream3

Compute 3-D streamline data

## Syntax

```XYZ = stream3(X,Y,Z,U,V,W,startx,starty,startz) XYZ = stream3(U,V,W,startx,starty,startz) XYZ = stream3(...,options) ```

## Description

`XYZ = stream3(X,Y,Z,U,V,W,startx,starty,startz) ` computes streamlines from vector data `U`, `V`, `W`.

The arrays `X`, `Y`, and `Z`, which define the coordinates for `U`, `V`, and `W`, must be monotonic, but do not need to be uniformly spaced. `X`, `Y`, and `Z` must have the same number of elements, as if produced by `meshgrid`.

`startx`, `starty`, and `startz` define the starting positions of the streamlines.

The returned value `XYZ` contains a cell array of vertex arrays.

`XYZ = stream3(U,V,W,startx,starty,startz) ` assumes the arrays `X`, `Y`, and `Z` are defined as `[X,Y,Z] = meshgrid(1:N,1:M,1:P)` where ```[M,N,P] = size(U)```.

`XYZ = stream3(...,options) ` specifies the options used when creating the streamlines. Define `options` as a one- or two-element vector containing the step size or the step size and the maximum number of vertices in a streamline:

```[stepsize] ```

or

```[stepsize, max_number_vertices] ```

If you do not specify values, MATLAB® software uses the default:

• Step size = 0.1 (one tenth of a cell)

• Maximum number of vertices = 10000

Use the `streamline` command to plot the data returned by `stream3`.

## Examples

collapse all

Plot 3-D streamlines from data representing air currents over regions of North America.

```load wind [sx,sy,sz] = meshgrid(80,20:10:50,0:5:15); streamline(stream3(x,y,z,u,v,w,sx,sy,sz)) view(3);``` 